The once-promising career of former A's right-hander Jarrod Parker is coming to an end.
Parker told the San Francisco Chronicle on Tuesday that he has retired from baseball following two serious injuries to his pitching elbow, and later tweeted that his playing days were over. The righty is in the process of filing his official retirement papers.
"I'm not entertaining any offers, let's put it that way," Parker told the Chronicle. "I'm just working through the logistical stuff."

Parker, still only 29 years old, underwent a second surgery for a fractured medial epicondyle bone in his right elbow in 2016. Parker told the Chronicle he has healed well from the surgery but has refrained from throwing competitively again.
"Your arm will tell you when it's done, and it did," said Parker. "It just sucks, being somewhat younger."
Parker was an ace in the making for Oakland just five short years ago. He broke out as a 23-year-old in 2012, compiling a 13-8 record and 3.47 ERA en route to a fifth-place finish in American League Rookie of the Year voting. Parker then followed up with a 12-8 record and 3.97 ERA over 32 starts in '13, setting a franchise record by making 19 consecutive starts without a loss. He picked up his lone postseason victory that fall, allowing three runs over five innings in the A's 6-3 victory over the Tigers in Game 3 of the American League Division Series.
Parker appeared to have the inside track as the A's Opening Day starter to begin 2014, until he tore his ulnar collateral ligament and was forced to undergo Tommy John surgery for a second time. The righty was back on a Minor League mound just 13 months later and ultimately broke his elbow during a rehab start for Triple-A Nashville in May 2015.

"He was one of the most talented young pitchers in the game," A's vice president of baseball operations Billy Beane told the Chronicle, "and the organization was at such a critical point of playoff runs. To have a guy with that kind of talent, and boom, he's extracted -- that was a huge blow."
Parker made yet another attempt at a comeback, but he shut it down for good when his elbow fractured again in March 2016. The Chronicle reports that Parker is pursuing a career in medical science with hopes of educating fellow pitchers and paying his experiences forward.
"I'd like to pass along that knowledge and information," Parker said. "I know the mental battles -- and I know there is light at the end of the tunnel."